duality, non-duality and beyond

"The undisturbed state of being is bliss; the disturbed state is what appears as the world. In non-duality there is bliss; in duality -- experience. What comes and goes is experience with its duality of pain and pleasure. Bliss is not to be known. One is always bliss, but never blissful. Bliss is not an attribute." - Nisargadatta, I Am That

So, are duality and non-duality both existential and not the unmanifest beyond? The unmanifest beyond is not non-dual because non-duality is a state? Then, perhaps "I Am" does not imply the unmanifest beyond, but the state of non-duality.  Even "I Am", then, is not absolute, and is, therefore, inferior.